This invention relates generally to a wrench adapted for use in connecting and disconnecting rod joints of a hollow stem auger drill.
More particularly, this invention, relates to a wrench adapted to hold a drill rod in place within a hollow stem auger and prevent the rod from turning while tripping rod into or out of the auger.
The drills with which the wrench of this invention is used are of the type known generally as hollow stem auger drills such as those manufactured by C.M.E., Acker and Mobile Drilling Company. Such drills are conventionally used to obtain soil or core samples from exploratory bore holes.
The drill string itself comprises primary sections of tubular pipe having helical auger flights on the external surface and having a bit disposed on the lower end of the bottommost section. Adjacent sections are coupled together by means of mating keys and key ways, which transmit rotary motion, and are secured longitudinally by means of a bolt or stud. A secondary drill string comprising sectional rods terminating in a bit or sample retrieving device, typically a core bit and core barrel, is disposed within the hollow stem auger. A surface rig is arranged to rotate either or both the primary and secondary drill strings and to hoist either or both out of the hole. Both the surface rig and the primary and secondary drill strings are, as noted before, conventional in the art.
Retrieval of a sample obtained by operation of the secondary drill string is accomplished by hoisting, or tripping, the drill rods out of the hole. During the procedure, the primary string or hollow stem auger, remains in the hole. Tripping secondary drill rods out of the hole requires hoisting the drill string a section at a time, disconnecting or breaking each rod joint and stacking the rod sections until the sample carrier reaches the surface. It is to be noted that rod sections of the secondary drill string are conventionally connected by means of threaded joints.
It is conventional practice in tripping the drill string out of the hollow stem auger to first hoist the string to a level whereat a rod joint is disposed above the top of the uppermost auger section. A pair of slip jaws or pipe vice anchored on the auger section top are then placed to secure the drill string against vertical movement. A pair of pipe wrenches, one above the rod joint and the other below it, are then used to break the rod joint and disconnect the top rod section from the remainder of the string. The string is then again hoisted to expose the next rod joint and the procedure is repeated until the entire string is recovered from the hole. A reverse of this procedure is employed to replace the drill string in the hole and continue drilling.
As may be appreciated, the present procedure requires use of three separate tools; the slip jaws and two pipe wrenches, and requires two men for operation of the pipe wrenches to make or break rod joints. Most rigs of this sort operate with a two man crew, the driller and his helper. Thus, while the driller is engaged with operation of a wrench, he necessarily is removed, from the controls of the drill rig.